Flexible metal hoses or conduits made from thin sheet metal ribbons which are convoluted and joined at their edges are commercially available from Hose Master Inc., assignee of the present invention. A so-called “interlocked” conduit is one example of such conduits. Interlocked conduit use thin metal ribbons wound helically with their convolutions secured together by reversely curved ribbon edges which are interlocked. The interlocked edges permit limited play between adjacent convolutions so the conduit can be flexed by a user. U.S. Pat. No. 4,197,728, issued Apr. 15, 1980, discloses conduit constructed in this manner.
Other flexible metal conduit constructions have been proposed in which flexibility is gained primarily by the manner of formation of the conduit convolutions. U.S. Pat. No. 4,486,484 issued Dec. 4, 1984, discloses such a conduit formed from convoluted metal ribbon which is corrugated. In this construction the helical corrugations provide flexibility while the joint between the convolutions is relatively inflexible. Other corrugated convoluted conduits have been proposed. U.S. Pat. No. 5,158,814 to Foti depicts another type of hose construction, hereinafter referred to as “Corrugated.” The '814 patent to Foti is incorporated herein by reference.
Helically wound flexible hose is also commonly referred to as “stripwound” metal hose. There are five basic types of stripwound hose.
1) “Roughbore interlocked” is hose in which the strip is formed with legs that interlock to form a tight and rugged construction.
2) “Smoothbore interlocked” is hose made by adding another steel strip inside a roughbore hose to provide a liner having a smooth inner surface, thereby reducing damage to any sensitive materials that are placed within the hose.
3) “Packed interlocked” is hose made by adding a packing to interlocked hose to minimize leakage through the hose profile. The most effective packings are made from resilient materials such as elastomers. Other possible packing materials are stainless steel and copper.
4) “Squarelocked hose” is hose where the helical strip is formed into square shapes that are locked together. These hoses are extremely flexible and are primarily used as protective covering for wires, cables and other hoses.
5) “Corrugated” stripwound hose.
The smoothbore interlocked hose is suited for dry bulk pneumatic conveyance. This hose is produced with a durable armor and an abrasion-resistant liner to achieve a high degree of strength and flexibility.
The hose is attached to a fitting or coupler that allows the hose to be interconnected with a source or destination of the material conveyed within the hose. Selecting a proper fitting for a particular application is determined by the mating fittings to which the hose assembly, i.e., hose plus hose fitting, will be attached. Once the mating fittings have been identified, the hose fittings should complement the mating fittings in type, size and alloy. Even though the selection of hose fittings is determined by the mating fittings, it is a good practice to confirm that the fittings used in any application are appropriate for the particular environment. Any necessary changes should be made to ensure that the fittings are chemically and physically compatible with the application's environment.
Referring now to the drawings, FIGS. 1–4 depict various examples of alternative prior art connections between a hose and a fitting. These alternative connections are also depicted in a Catalog entitled “Industrial Metal Hose Products” provided by Hose Master Inc. Copyright 2001 by Hose Master Inc.
FIG. 1 shows a hose assembly having a fitting 10 attached to an interlocked hose 12 using an epoxy 14. The fitting has a notch 16 of larger diameter to accommodate the presence of the hose 12 in a region of overlap 18 between the hose and fitting.
In FIG. 2, a hose assembly includes a fitting 20 attached to an interlocked hose 22 by use of a weld or braze joint 24. If possible, the weld joint 24 is made on an interior diameter of the engagement between the hose and the fitting. As in the assembly illustrated in FIG. 1, the fitting includes a notch 26 of larger diameter that defines a region of overlap 28 between hose and fitting. Welding is not recommended, however, for packed interlocked hose, as the packing may be damaged by the relatively high welding temperature.
In FIG. 3, a hose assembly includes a fitting 30 attached to an interlocked hose 32 using two weld or braze joints 34, 35. Welding to an interior diameter provides a smooth transition between hose and fitting to prevent the product carried within the hose from becoming damaged. Providing a second weld joint 35 on the outside diameter of the fitting 30 tends to prevent contamination from entering an interface between the fitting and hose from the outside and also provides additional strength. As shown in FIGS. 2 and 3, a notch 36 of an increased inside diameter of the fitting 30 defines a region of overlap 38 between the fitting and the hose.
In FIG. 4, a hose assembly is depicted that includes two fittings 40, 41 attached to an interlocked hose 42. A first fitting 40 has a threaded interior that threadingly engages corrugations 43 in an outer diameter of the hose 42. An outer surface of the first fitting 40 is threaded to engage a threaded interior of the second fitting 41. A high temperature packing material 45 is used to seal against leakage. The second fitting 41 defines a notch 46 of slightly greater diameter against which the end of the hose 42 abuts.